TCP means it is on the(74)layer and IP means it is on the(75)layer.A．networkB．transportC．data linkD．application

● GIF files are limited to a maximum of 8 bits/pixel, it simply means that no more than 256 colors are allowed in （74） .

（74）A. an image B. a file C. a window D. a page

● A glue that holds the whole Internet together is the network layer protocol,(71). Unlike most older network layer protocols, it was designed from the beginning with internetworking in mind. Its job is to provide a -(72) way to transport datagrams from source to destination, without regard to whether these machines are on the same network or whether there are other networks in between them.

Communication in the Internet works as follows. The (73)layer takes data streams and breaks them up into datagrams. Each datagram is transmitted through the Internet, possibly being fragmented into smaller units as it goes. When all the pieces finally get to the destination machine, they are reassembled by the

(74) layer into the original datagram. This datagram is then handed to the transport layer, which inserts it into the receiving process' input stream.

An IP datagram consists of a header part and a text part. The header has a (75) part and a variable length optional part.

(71) A. IP (Internet Protocol)

B. IP (Interworking Protocol)

C. TCP (Transport Control Protocol)

D. TCP (Transfer Communication Protocol)

(72) A. best-quality

B. quality-guaranteed

C. connection-oriented

D. best-efforts

(73) A. data link

B. transport

C. network

D. application

(74) A. data link

B. transport

C. network

D. application

(75) A. 40-byte fixed

B. 64-byte fixed

C. 20~64 bytes variable

D. 20-byte fixed

In the open systems interconnection (OSI) reference model, "layer" means one of seven conceptually complete,(71) arranged groups of services, functions, and protocols, that extend across all open systems.Application layer provides means for the application(72) to access the OSI environment. Presentation layer provides for the selection of a common syntax for representing data.(73) layer provides the means necessary for cooperating presentation entities to organize and synchronize their dialog and to manage their data exchange. Transport layer provides a reliable end-to-end data transfer service. Network layer provides for the entities in the transport layer the means for transferring blocks of data, by(74) and switching through the network between the open systems in which those entities reside. Data link layer provides services to transfer data between network layer entities. Physical layer provides the mechanical, electrical, functional, and procedural means to establish, maintain and(75) physical connections for transfer of bits over a transmission medium.

A．rankly

B．levelly

C．layered

D．hierarchically

SQL Server is a RDBMS( Relational Database Management System)made by Microsoft. This means that the data is stored in two dimensional(74)

A．documents

B．databases

C．files

D．tables

A transport layer protocol has several responsibilities. One is to create a process-to-process (program-to-program) communication; TCP uses port (71) to accomplish this. Another responsibility of a transport layer protocol is to create a (72) and error-control mechanism at the transport level. TCP uses a sliding (73) protocol to achieve flow control. It uses the acknowledgment packet, time-out, and retransmission to achieve (74) control. The transport layer is also responsible for providing a connection mechanism for the application program. The application program sends (75) of data to the transport layer. It is the responsibility of the transport layer at the sending station to make a connection with the receiver.

（71）

A．numbers

B．connections

C．diagrams

D．resources

● TCP/IP （71） layer protocols provide services to the application （72） running on a computer. The application layer does not define the application itself, but rather it defines （73） that applications need—like the ability to transfer a file in the case of HTTP. In short, the application layer provides an （74） between software running on a computer and the network itself. The TCP/IP application layer includes a relatively large number of protocols, with HTTP being only one of those. The TCP/IP （75） layer consists of two main protocol options—the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP).

A. Application Layer

B. Transport Layer

C. Internet Layer

D. Network Access Layer

● (75) means thata source program file can be compiled and executed on different computers.

(75)

A. Portability

B.Usablity

C.Recovery

D.Mobility

● A transport layer protocol has several responsibilities. One is to create a process-to-process (program-to-program) communication; TCP uses port （71） to accomplish this. Another responsibility of a transport layer protocol is to create a （72） and error-control mechanism at the transport level. TCP uses a sliding （73） protocol to achieve flow control. It uses the acknowledgment packet, time-out, and retransmission to achieve （74） control. The transport layer is also responsible for providing a connection mechanism for the application program. The application program sends （75） of data to the transport layer. It is the responsibility of the transport layer at the sending station to make a connection with the receiver.

（71）

A. numbers

B. connections

C. diagrams

D. resources

（72）

A. procedure

B. function

C. route

D. flow

（73）

A. path

B. window

C. frame

D. diagram

（74）

A. packet

B. time

C. error

D. phase

（75）

A. ports

B. streams

C. packets

D. cells

-Does "am"___ afternoon

-No, it morning.

A. means，mean

B. means, means

C. mean, means

TCP functions at the Open System Interconnection(OSI)(61)layer, or Layer 4. Its chief responsibility is to ensure(62)end-to-end connectivity. IP, located one layer down, at the OSI network layer, or Layer 3, communicates the addresses of each(63)sender and receiver to the routers along the way. Routers and Layer 3 switches can read IP and other Layer 3(64). This information, combined with routing tables and other network intelligence, is all it takes to get(65)the room or around the world via TCP/IP.

A．transpose

B．translate

C．transmit

D．transport

Each machine supporting TCP has a TCP transport entity, either a library procedure, a user process, or part of the kernel. In all case, it manages TCP streams and (71) to the IP layer. A TCP (72) accepts user data streams from local process, breaks them into pieces not exceeding 64KB, and sends each piece as a separate IP (73). When datagrams containing TCP data arrive at a machine, they are given to the TCP entity, which reconstructs the original byte streams.The IP layer gives no guarantee that datagrams will be delivered properly, so it is up to TCP to time out and (74) them as need be. Datagmms do arrive may well do so in the wrong order, it is also up to TCP to (75) them into messages in the proper sequence.

A．calls

B．interfaces

C．links

D．produces

TCP/IP is a communication protocol, which provides many different networking services. The TCP/IP Internet protocol suite is formed from two standards: the TCP （Transmission Control Protocol） and the IP（Internet Protocol）.

（72） means it is on the transport layer.

A.ISO

B.IP

C.OSI

D.TCP

is a connectionless TCP/IP transport layer protocol.

A．FTP

B．UDP

C．1P

D．ICMP

● Each machine supporting TCP has a TCP transport entity, either a library procedure, a user process, or part of the kernel. In all case, it manages TCP streams and （71） to the IP layer. A TCP （72） accepts user data streams from local process, breaks them into pieces not exceeding 64KB, and sends each piece as a separate IP （73） . When datagrams containing TCP data arrive at a machine, they are given to the TCP entity, which reconstructs the original byte streams. The IP layer gives no guarantee that datagrams will be delivered properly, so it is up to TCP to time out and （74） them as need be. Datagrams do arrive may well do so in the wrong order, it is also up to TCP to （75） them into messages in the proper sequence.

（71）

A. calls

B. interfaces

C. links

D. produces

（72）

A. connection

B. file

C. entity

D. destination

（73）

A. datagram

B. stream

C. connection

D. transaction

（74）

A. reassemble

B. reduce

C. re-create

D. retransmit

（75）

A. reassemble

B. reduce

C. re-create

D. retransmit